Dyeing acetyl cellulose.



. UNITED S TES PATENT our-ion. i

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No Drawing. Application filed November 23, i907. Serial in. 403,573. (Specimena) To all whom it may concern:

Be it known that I, EMIL KNOEVENAGEL, professor of chemistry man Emperor,'resid1ng the Grand Duchy of Baden, Germany, have invented certain new and useful Improvements Relating to the Art of Dyeing Acetyl Cellulose, of which the following is a specification. t

Acetyl cellulose and filaments or other products made from the same are not mois tened by waterv and are therefore not dyed at all or only feebly by aqueous solutions. of

V sumes intense colors in .dyeing.

dyestuffs according to ordinary'processes of I have'discovered, -that acetyl-cellulose aslutions, if the surface of the fabric of acetylcellulose has 'be'enpreviously modified, by treatment with organic substances or their aqueous solutions, which are capable of swelling up or inflating acetyl-cellulose, such as alcohol, acetic acid and acetone.

The process consists in treating the 'filament or other product of acetyl-cellulose, at ordinary or at elevated temperature with such substances for a period depending on the nature of the organic substance selected, and on whether the said substanceis used per se or in aqueous solution, preferably by introducing the said fabric substance orits aqueous solution and allowing it-to remain therein for the required time, then wringin the fabric, rinsing it with water, if required, and finally dyeing the fabric in an aqueous dyestufi solution by one of; the ordinary dyeing processes. For instance, filaments of acetyl-cellulose maybe allowed to remain in 50per cent. aqueous alcohol or in dilute glacial acetic acid or in a mixture of alcohol and acetone in equal volumes for 12 hours at the temperature of an ordinary living room. Concentrated alcohols and the like will also enand ether, enhance to some extent the ca-- pacity of cellulose acetate forv the absorption of dyestuffs in the '-process of dyeing in aqueous solutions, providedthat the acetylcellulose is allowed toremain in such liquids or theirrsolutions fora considerable time.

Even solutions of soap, especially when used a subject of. the Ger at Heidelberg, in,

nm and others fiir .Anilinfabrikationaqueous dy'estuff sointo the saidvarious dyestuffs one special bat 'hol adhering to the that this process results in a substantial savlose to .be quick y' and completely- Even substances warm, act in the same directiombut more feeblythan'for instance, dilute alcohols.

The dyestuffs,

which are not soluble or only 5 ar 1 soluble in water, p mgy such as the anthracene dyeup from aqueous cellulose substantia dye-baths by the acetyl repared as described and yield y more intense colorations than spec men armamen Patented June 14,1910,

such for example, as meth- .ylene blue, malachite green, fuchsin, stainand even those dyestuffs stuffs, also vat dye stufls are rapidly taken acetyl-cellulose which has not beenlthus prepared.

n has already beenproposed (see German.

Patent-No. 193135 of the Aktiengesellschaft at Berlin) for the dyeing of acetyl-cellulose,'to add organic substances, such as alcohol, acetic acid, and

acetone directly'to the aqueous solutions of a the dye-stuffs. The addition of such substances-to aqueous dye-stufl solutions may,

however, be dispensed with, if accord to the above process the acetyl-cellulose, be ore dyeing it in aqueous solution preliminary treatment with substances or mixtures water. that the actual dyeing process may be performed in aqueous solution in the manner well-known for basic or acid dyestuffs or for vat-dyestuffs, so "that for dyein the most only, for

is subjected to suitable organic of the same with instance a bath; of

allowed to remain for the required time and then carefully relieved of the aqueous alcosame, by wringing, so

ing of alcohol, in comparison with the use of .dyest-uif baths mixed with alcohol.

Even if according to the'present process,

aqueous alcohol, is required. In this bath the acetyl-cellulose is This process affords the advantage,

acetyl cellulose by proit out such as still adhere in this process after the acetyl cellulose has been rinsed, be added to aqueous solutions of dye-stuffs and if attempts be made to dye therein acetyl-cellulose which has not been previously treated, the dyestufi iseither not "taken up at all or only vrybadly.v

What I claim is:-- v 4 I 1. The improvement 111 the art of dye ng acetyl-cellulose, which consists m treating the acetyl-cellulose with aqueous solutions of the herein described organic substanws which are capable of swelling acetyl cellnlose, then wrin the prodi ct rmsmg it with water an then dye ng 1t meql eous dyestufi solution, substantie y as described.

2. The improvement in the art of dye ng acetyl-eellulose, which consists in treating the acetyl-cellulcse with diluted alcohol, then wrin 'ng theproduct, rinsing it with water an dyeing 1t in .aqueous dyestuffsolution, substantlally as described.

In testimony whereof I have set my hand in the presence of two subscribing witnesses.

Witnesses:

Heme Lemon, Joe. H.111 

